from math import *
x1, y1, x2, y2 = map(float, input().split())
print(hypot(x1 - x2, y1 - y2)) from math import * x1, y1, x2, y2 = map(float, input().split()) x1 map(float, input().split()) map float input().split() ().split () input split y1 x2 y2 print(hypot(x1 - x2, y1 - y2)) print hypot(x1 - x2, y1 - y2) hypot x1 - x2 x1 x2 y1 - y2 y1 y2 x2, y2 = map(float, input().split()) map(float, input().split()) x2 x1, y1, x2, y2 = map(float, input().split()) map(float, input().split()) x1 y1, x2, y2 = map(float, input().split()) map(float, input().split()) y1 y2 = map(float, input().split()) map(float, input().split()) y2
from math import *
x1, y1, x2, y2 = map(float, input().split())
print(hypot(x1 - x2, y1 - y2))
